A soft corneal contact lens which improves the color discrimination of a color-blind person when applied to one eye only, said lens comprising a clear, soft, corneal contact lens having on the central portion of its exterior surface a thin layer of red coloration characterized as being insoluble in water but soluble in aromatic hydrocarbon; light passing through the red layer having substantially all its transmissions above about 6000 .ANG.; said red layer continuously covering substantially all the light normally admitted to the pupil of the eye during the daytime and being in line with the axis of the pupil; said lens being sufficiently large to enable ready and stable centration without jeopardizing oxygen transmission.
This invention relates to the use of corneal contact lenses for the correction of color blindness, in particular, soft or gas-permeable lenses.
U.S. Pat. No(s). 3,586,423 and 3,701,590 describe red-colored contact lenses which can be used to correct color blindness. In particular lenses illustrated in these patents and those made commercially under those patents are colored throughout with a red coloration. Whereas such coloration throughout the lens is satisfactory for so-called hard lenses made from plastic, it has been difficult to fashion a soft lens or a gas-permeable lens wherein the color remains uniformly distributed throughout the lens.
One object of the present invention is to provide a soft or gas-permeable contact lens containing red coloration which can be used for the correction of color blindness and which is relatively simple to manufacture.
Other objects and advantages of this invention will be apparent from the description and claims which follow taken together with the appended drawings.